Regional anesthesia (RA) procedures and, in particular, peripheral nerve blocks for surgical anesthesia and postoperative analgesia, are typically performed for pain relief during and after surgical procedures. RA is typically used for labor, chronic pain, in epidural, subdural or spinal procedures, and for plexus blocks and blocks of peripheral nerves (e.g. axillary and interscalene blocks of the brachial plexus, femoral nerve, sciatic nerve and popliteal nerve blocks). Peripheral nerve blocks, when properly performed, can be superior to general anesthesia, as they can provide effective analgesia with few side effects and can hasten patient recovery.
RA is typically performed in a separate block-placement area or in the operating room. Typically the anesthesiologist or practitioner performing the block requires ancillary staff to assist in the procedure (e.g. localizing the nerve with an ultrasound probe, holding an ultrasound probe in place over the nerve, holding and injecting the local anesthetic, etc.) while the practitioner carefully inserts the needle and then holds the needle in place at the injection site. Indeed, successful block placement has often required the use of three, four or more hands. Most practitioners require nurses to be present to perform some of the duties, such as pushing the local anesthetic solution of choice through a syringe and needle placed at the injection site, once the needle has been stabilized over the nerve of interest by the practitioner. This need for “another set of hands” can be a disadvantage, as “feel” is important to the practitioner for knowing if the needle is in the right place.
Historically, due to comparatively unreliable success rates and often time-consuming block placement procedures, RA has been thought of as a second choice to general anesthesia, and often is performed only if necessary. The clinical practice of regional anesthesia has thus been limited by inherent difficulties that to date may only be overcome with expertise in the area. Proper RA practice necessitates significant hands-on clinical experience, along with a strong commitment to improve one's skills to achieve success. RA requires a working knowledge of anatomy and superior hand dexterity in order to reliably accomplish numerous tasks, generally on a conscious, nervous and/or fidgety patient. Such tasks typically include localization of a target nerve, localization of an injection site, appropriate placement of a needle at the injection site, stabilization of the needle, infusion of medication(s), and monitoring a response. All of these steps require significant training, time and commitment. Often the time constraints of busy surgical centers have limited the application of RA even further.
Although uncommon, the risks of RA include nerve injury, permanent nerve damage, intravascular injection of local anesthetic resulting in systemic toxicity, and pneumothorax (e.g. following supraclavicular block). However, these risks can be minimized by proper localization of the target nerve and placement of the needle at the injection site, followed by controlled infusion of the local anesthetic.
While successful block of a target nerve typically depends upon accurate placement of local anesthetic in sufficient amounts around the nerve, locating the target nerve has often proved problematical in patients with difficult landmarks. Utilization of new technology, such as evoking parathesias and using peripheral nerve stimulators (PNS) or ultrasound for localization, has typically been haphazard and can often further complicate the process rather than simplify it. The techniques of evoking parathesias and peripheral nerve stimulation are essentially “blind” procedures, since they rely on indirect evidence of needle-to-nerve contact. Seeking nerves by trial and error and random needle movement can cause complications. Therefore, proper peripheral nerve stimulation for nerve localization, while holding promise for improving block success and decreasing complications, requires clinical experience and should only be used by trained individuals. Unfortunately, typically only one “trained individual” is present for the placement of the nerve block (i.e. an anesthesiologist, nurse anesthetist or other practitioner), and this individual only has two hands where often many hands are required simultaneously.
With the advent and introduction of ultrasound into clinical practice of RA, these issues have only become more compounded. Trying to position and prep the patient, use PNS or an ultrasound probe to find the nerve, determine an injection site close to the nerve, place the needle at the injection site, and inject the medication while maintaining the needle position during injection can be very difficult to master without a well-trained ancillary staff. However, increasing demands are often placed upon regional anesthesia practitioners such that extra personnel are not always available to assist the practitioner perform the procedures. Further, sometimes situations occur where it would be beneficial if the procedure were performed in a cramped space at the patient's bedside, where only one individual has adequate access to the patient. There are also situations in which the practitioner must move quickly from one surgical suite to another in order to perform blocks on multiple patients over a short period of time. In such situations, it would be beneficial if the practitioner were able to perform the needed RA procedures alone, or with minimal ancillary assistance. It would also be helpful if the practitioner had sufficient supplies and equipment that were also able to travel with him from one surgical suite to another. In such situations a mobile medical cart has often come in handy.
There are many examples in the prior art of mobile or portable medical carts. For example, U.S. Pat. No. 6,663,569 to Wilkins et al. discloses a portable ultrasound cart holding the electronic circuitry of the ultrasound system, a control panel for controlling the system, and a display. The control panel has an articulating mechanism enabling an adjustable height to accommodate the height of the practitioner, and also enabling the control panel to be moved forward and backward to accommodate users in both the sitting and standing positions. U.S. Pat. No. 6,419,654 to Kadan discloses a diagnostic needle and arthroscopy lavage system that includes a cart for housing a video monitor, a camera, an optic and light system, a VCR, an air compressor, an irrigation pump, suction unit, collection canisters and an arthroscope. U.S. Pat. No. 5,712,482 to Gaiser et al. discloses a portable cart-based electronic imaging system wherein an X-ray screen is mounted on the cart by a manipulable arm assembly enabling selective positioning movement of the screen horizontally, vertically, and angularly to receive the radiation beam.
While prior art medical carts may be useful for their intended purposes, currently there is no medical cart available that provides all of the equipment and supplies typically required for performing a successful RA block with little or no assistance. To date, no integrated means or system exists to assist with the many steps required for successfully performing a regional nerve blockade. Thus, it would be desirable to provide a system for aiding the RA practitioner in the steps of nerve localization, needle placement, needle stabilization, and medication infusion with minimal or no ancillary assistance. It would also be advantageous to have an infusion device that can provide feedback to the practitioner regarding the injection rate, resistance to injection, and pressure profile of the medication. It would also be desirable if such equipment were available on a cart for quickly and easily transporting the equipment to the block-placement area.